elr10.c

数值分析的常用算法

  #include "stdio.h"
  #include "elr1.c"
  main()
  { int i,j;
    double y[3],z[3][11],t,h,x;
    void  elr1f();
    y[0]=-1.0; y[1]=0.0; y[2]=1.0;
    t=0.0; h=0.01;
    elr1(t,y,3,h,11,z,elr1f);
    printf("\n");
    for (i=0; i<=10; i++)
      { x=i*h;
        printf("t=%5.2f\n",x);
        for (j=0; j<=2; j++)
          printf("y(%d)=%e  ",j,z[j][i]);
        printf("\n");
      }
    printf("\n");
  }
 
  void elr1f(t,y,n,d)
  int n;
  double t,y[],d[];
  { t=t; n=n;
    d[0]=y[1]; d[1]=-y[0]; d[2]=-y[2];
    return;
  }